From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0D7FDC17498 for ; Tue, 5 Nov 2019 14:49:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D7F17217F5 for ; Tue, 5 Nov 2019 14:49:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="S55SVB4X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389038AbfKEOto (ORCPT ); Tue, 5 Nov 2019 09:49:44 -0500 Received: from mail-m975.mail.163.com ([123.126.97.5]:41496 "EHLO mail-m975.mail.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727889AbfKEOto (ORCPT ); Tue, 5 Nov 2019 09:49:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=fmCmuOAiEUwEwfeCcX FYBqOu7taXOPv5Mn5DJrGyiqw=; b=S55SVB4XKcW2KybHxCblxfDEYjf39VXJHa 9PxmKcMsjybQcsDcQjhwRDdgN6mLTwVVNX4CTcbIApI9QLE3jRBQZADnNtizuIkh bGbz570JGl7Ns+z6jp2Rj1ub4+do+qBEKtdk51uzr4WLAIuGDQDSiZhGQP2W92Be +6L1Zee4k= Received: from localhost.localdomain (unknown [202.112.113.212]) by smtp5 (Coremail) with SMTP id HdxpCgD3iCLvi8FdNofqJw--.256S3; Tue, 05 Nov 2019 22:49:23 +0800 (CST) From: Pan Bian To: Greg Kroah-Hartman , Himadri Pandya , YueHaibing , Colin Ian King Cc: devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, Pan Bian Subject: [PATCH] staging: rtl8192e: fix potential use after free Date: Tue, 5 Nov 2019 22:49:11 +0800 Message-Id: <1572965351-6745-1-git-send-email-bianpan2016@163.com> X-Mailer: git-send-email 2.7.4 X-CM-TRANSID: HdxpCgD3iCLvi8FdNofqJw--.256S3 X-Coremail-Antispam: 1Uf129KBjvJXoW7tr48JF48Ww4fAw1xXrWxXrb_yoW8Jw1UpF 4rGwnIyrWUZr48u3ykAFWIgryFka1SgF9agay3X3yrZrZxCw1rXryqvFyjqr45CrZ3CF4a qFn5Kr15uan8WaDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07UXeOXUUUUU= X-Originating-IP: [202.112.113.212] X-CM-SenderInfo: held01tdqsiiqw6rljoofrz/xtbBURNkclaD5I2j7AAAsn Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The variable skb is released via kfree_skb() when the return value of _rtl92e_tx is not zero. However, after that, skb is accessed again to read its length, which may result in a use after free bug. This patch fixes the bug by moving the release operation to where skb is never used later. Signed-off-by: Pan Bian --- drivers/staging/rtl8192e/rtl8192e/rtl_core.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/staging/rtl8192e/rtl8192e/rtl_core.c b/drivers/staging/rtl8192e/rtl8192e/rtl_core.c index f932cb15e4e5..cdcb22f96ed9 100644 --- a/drivers/staging/rtl8192e/rtl8192e/rtl_core.c +++ b/drivers/staging/rtl8192e/rtl8192e/rtl_core.c @@ -1616,14 +1616,15 @@ static void _rtl92e_hard_data_xmit(struct sk_buff *skb, struct net_device *dev, memcpy((unsigned char *)(skb->cb), &dev, sizeof(dev)); skb_push(skb, priv->rtllib->tx_headroom); ret = _rtl92e_tx(dev, skb); - if (ret != 0) - kfree_skb(skb); if (queue_index != MGNT_QUEUE) { priv->rtllib->stats.tx_bytes += (skb->len - priv->rtllib->tx_headroom); priv->rtllib->stats.tx_packets++; } + + if (ret != 0) + kfree_skb(skb); } static int _rtl92e_hard_start_xmit(struct sk_buff *skb, struct net_device *dev) -- 2.7.4